Extend the expiry of an ENS subname in the NameWrapper. Subnames have their own expiry that cannot exceed the parent name's expiry. This tool extends a subname's expiry. Who can call this: - The parent name owner (always) - The subname owner (only if CAN_EXTEND_EXPIRY fuse is burned on the subn...
Part of the Name Whisper MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.
AI agents use extend_subname_expiry to create or modify resources in Name Whisper. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call extend_subname_expiry repeatedly, creating or modifying resources faster than any human could review. Intercept's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Name Whisper.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
tools:
extend_subname_expiry:
rules:
- action: allow
rate_limit:
max: 30
window: 60See the full Name Whisper policy for all 34 tools.
Agents calling write-class tools like extend_subname_expiry have been implicated in these attack patterns. Read the full case and prevention policy for each:
Other tools in the Write risk category across the catalogue. The same policy patterns (rate-limit, validate) apply to each.
Extend the expiry of an ENS subname in the NameWrapper. Subnames have their own expiry that cannot exceed the parent name's expiry. This tool extends a subname's expiry. Who can call this: - The parent name owner (always) - The subname owner (only if CAN_EXTEND_EXPIRY fuse is burned on the subname) Use cases: - Extending subnames you've issued to users - Self-extending your own subname (if CAN_EXTEND_EXPIRY is set) - Keeping organizational subnames active. It is categorised as a Write tool in the Name Whisper MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Add a rule in your Intercept YAML policy under the tools section for extend_subname_expiry. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the Name Whisper MCP server.
extend_subname_expiry is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the extend_subname_expiry rule in your Intercept policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the Intercept policy for extend_subname_expiry. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
extend_subname_expiry is provided by the Name Whisper MCP server (namewhisper/ens-tools). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Open source. One binary. Zero dependencies.
npx -y @policylayer/intercept